This episode reveals that Bashir gave his diaries to Dax so she could understand him better, since they contained his innermost thoughts. I wonder if his diaries contain information about his genetic enhancements?

Sisko tells Keiko that "Miles was a fine officer, and a fine man." There are other references to "your officers". O'Brien's rank has been all over the place in Trek, but generally he's been considered to be an enlisted man, not an officer. Indeed, this very episode has him talking about "career officers" as being something he is not.

When Keiko complains about O'Brien drinking coffee after 15:00, somebody says it might have been Tea. Keiko replies that "I checked the data clip. It contained a spectroscopic analysis. The liquid in Miles' cup consisted of vegetable-based oils and caffeine. It's coffee all right." Um, Tea also contains both vegetable oils and caffeine. And surely Keiko the botanist would know this?

Great Moment :

The relisation that Keiko's Big Coffee Clue was actually wrong, and he and Bashir were only saved by accident.

Plotline

O'Brien and Bashir help the T'Lani and Kellerun species to destroy the deadly "Harvesters", biological weapons of terrible power. But the former enemies are determined to destroy all knowledge of the weapons by killing everybody who could build them - including the Starfleet officers.